What is the evaluation and management of pathological nipple discharge?

Evaluation and Management of Pathological Nipple Discharge

For pathological nipple discharge in patients ≥40 years, initiate evaluation with diagnostic mammography (or digital breast tomosynthesis) plus ultrasound of both breasts, followed by image-guided core biopsy of any identified lesions, and if imaging is negative but discharge persists, proceed to surgical consultation for central duct excision. 1, 2

Distinguishing Pathological from Physiological Discharge

Pathological discharge is defined by at least one of the following characteristics:

• Spontaneous occurrence (not provoked) 1, 2
• Unilateral presentation 1, 2
• Single duct origin 1, 2
• Bloody, serous, or serosanguineous appearance 1, 2

Physiological discharge characteristics (requires NO imaging if screening mammography is current):

• Bilateral, multiple duct origin 1
• White, green, yellow, or milky appearance 1
• Only occurs when provoked 1
• No association with malignancy 1

Risk Stratification

Malignancy rates vary significantly by patient demographics:

• Overall malignancy rate in pathological discharge: 5-21% 2
• Ages 40-60 years: 10% malignancy risk 1
• Age >60 years: 32% malignancy risk 1
• Male patients with nipple discharge: 23-57% malignancy rate 1

Additional risk factors for malignancy:

• Presence of palpable mass 2, 3
• Bloody discharge (30.3% cancer rate vs 17.6% for serous) 4
• Age >50 years 3

Common pitfall: Serous, colored, or serosanguineous discharge should NOT be assumed benign despite traditional teaching—these carry similar malignancy risk to the general pathological discharge population (23.9%) 4

Diagnostic Algorithm by Age

Patients ≥40 Years Old

Initial imaging (both modalities are complementary):

• Diagnostic mammography or digital breast tomosynthesis (DBT) 1, 2
• Ultrasound of both breasts with special attention to retroareolar region 1, 2

Ultrasound technique optimization:

• Use standoff pad or abundant warm gel 2
• Apply peripheral compression and rolled-nipple techniques 2
• Ultrasound is more sensitive than mammography but less specific 1

Patients 30-39 Years Old

Either mammography or ultrasound initially, with clinical judgment guiding choice 5

Patients <30 Years Old

Ultrasound alone as initial imaging 5

Advanced Imaging Considerations

If initial mammography and ultrasound are negative but pathological discharge persists:

Ductography (galactography):

• Can demonstrate very small intraductal lesions 1
• Irregular stenosis on galactography strongly associated with malignancy 4
• Technical limitations: 10% inadequate studies, invasive, time-consuming 1

DBT-ductography (emerging technique):

• Improved sensitivity (95% vs 77%) and accuracy (96% vs 80%) compared to conventional galactography 1
• Identical specificity (80%) 1

MRI:

• Consider if initial imaging negative and high clinical suspicion 2

Cytological Evaluation

Cytology of nipple discharge has limited but specific utility:

• C5 (malignant) and C4 (suspicious) findings strongly associated with cancer 4
• Only 50% sensitivity for detecting underlying carcinoma 3
• High specificity justifies routine examination when discharge can be obtained 4
• Do not rely on cytology alone for exclusion of malignancy 3

Management Based on Imaging Results

If Lesion Identified on Imaging

Perform image-guided core needle biopsy for tissue diagnosis 2

• Ultrasound guidance preferred for localization 1
• Core biopsy superior to fine needle aspiration for definitive diagnosis 2

If All Imaging Negative but Pathological Discharge Persists

Surgical consultation for central duct excision or selective duct excision 2, 6

• Selective duct excision is the diagnostic gold standard with highest sensitivity and specificity 4
• Serves both diagnostic and therapeutic purposes 6

Common Benign Etiologies

Most common causes of pathological discharge (in order of frequency):

• Intraductal papilloma/papillomatosis: 35-48% 1, 2
• Duct ectasia: 17-36% 1

Mammographic findings of papilloma:

• Asymmetrically dilated ducts 1
• Circumscribed subareolar mass 1
• Grouped microcalcifications 1

Critical Pitfalls to Avoid

Do not dismiss non-bloody discharge as benign: Serous and colored discharge carry similar malignancy risk to the overall pathological discharge population 4

Do not skip imaging in males: Male patients have exceptionally high malignancy rates (23-57%) and require the same rigorous imaging evaluation as females 1

Do not rely on mammography alone: Sensitivity for malignancy detection ranges only 15-68% because lesions may be very small, lack calcifications, or be completely intraductal 1

Do not assume purulent discharge equals simple infection: Purulent discharge differs from pathological discharge but should not be assumed to have infection as the sole explanation without proper evaluation 5